a(n) = 3^n - n^10.

Terms

a(0) =1a(1) =2a(2) =-1015a(3) =-59022a(4) =-1048495a(5) =-9765382a(6) =-60465447a(7) =-282473062a(8) =-1073735263a(9) =-3486764718a(10) =-9999940951a(11) =-25937247454a(12) =-61916832783a(13) =-137856897526a(14) =-289249872007a(15) =-576636041718